Google is very proactive about how it sells its various products, be they pieces of software or hardware. The Nexus 10 tablet and the Google Play store are showing that clearly.
As it turns out, the Nexus 10 tablet is no longer absent from the Google Play store.
A use of a certain app called Nexus Availability Checker will show the availability, or lack of availability, of all Google Nexus devices.
The Nexus Availability Checker can be set to notify owners of Android devices when the status of a Nexus device changes.
Those who use this function have probably learned of the new development.